Field of the Invention
The present invention relates to, for example, a control device for a four-wheel electric vehicle including an in-wheel motor drive device, and particularly relates to a technique to control a motor on the basis of an open loop control method and a current feedback control method by a voltage equation for the motor in consideration of a parameter of the motor.
Description of Related Art
Hitherto, as a technique to control a motor, for example, a current feedback control method and a current open loop control method have been proposed.
Conventional Art 1 (Patent Document 1) <Current Feedback Control Method>
A control target torque command of output torque T is set in accordance with manipulation of an accelerator pedal by a driver of a vehicle. Next, d-axis and q-axis inductances are obtained beforehand on the basis of the set control target torque command, by using a motor output torque equation T=p×{Ke×Iq+(Ld−Lq)×Id×Iq}, and further by experimental measurement or the like, and a current command vector which is to be a control target for a current vector (Id, Iq) is set by using the values of the d-axis and q-axis inductances. A primary current Ia of the motor is controlled on the basis of the set current command vector, for each of d-axis and q-axis components thereof. As a control method, a method has been proposed in which, through PI feedback control, the value of an actual measured current vector (Id, Iq) of the motor is caused to coincide with the current command vector, thereby realizing the control target torque command as actual output torque T of the motor.
Conventional Art 2 (Patent Document 2) <Current Open Loop Control Method>
A method has been proposed in which all current sensors are removed for cost reduction and open loop control (forward control) is performed according to a motor circuit equation. In the proposed control method, an assist map in which torque T is associated with a current command vector is created beforehand, and a drive voltage is calculated by using a voltage circuit equation. The d-axis and q-axis inductances are handled as known parameters.